1. Field of the Invention
The invention relates to a heater, especially an auxiliary motor vehicle heater, with a burner in a combustion chamber which is surrounded by a generally pot-shaped die cast heat exchanger that has an inner and an outer part, between which an intermediate space is formed through which a heat exchange medium flows. Combustion gases emerging from the combustion chamber are discharged via an exhaust outlet connection.
2. Description of Related Art
One such heater is known, for example, from German Patent DE 38 39 244 C2 and its counterpart U.S. Pat. No. 4,944,454. In this known heater, the exhaust outlet connection, as in all heaters, is provided with a die cast heat exchanger on a burner head which is flanged to the heat exchanger. In other words, the burner head represents an additional component of the heater for collecting and discharging exhaust gas. Since the heat exchange medium does not flow through the burner head, in the entire area of the burner head, which comprises roughly one third of the volume of the heater, heat cannot be withdrawn from the hot exhaust gases.
In heaters, for example, auxiliary motor vehicle heaters, in which the heat exchanger is made of steel, providing exhaust gas connections passing through the heat exchanger without an additional burner head is known. In the case of die cast heat exchangers, this construction was not considered for a long time, since the associated sealing problems were considered insurmountable.